Aptitude - Ratio and Proportion - Discussion
Discussion Forum : Ratio and Proportion - General Questions (Q.No. 9)
9.
The sum of three numbers is 98. If the ratio of the first to second is 2 :3 and that of the second to the third is 5 : 8, then the second number is:
Answer: Option
Explanation:
Let the three parts be A, B, C. Then,
| A : B = 2 : 3 and B : C = 5 : 8 = |  |
5 x | 3 |  |
: | |
8 x | 3 | |
= 3 : | 24 |
| 5 | 5 | 5 |
 A : B : C = 2 : 3 : |
24 | = 10 : 15 : 24 |
| 5 |
| B = |
|
98 x | 15 | |
= 30. |
| 49 |
Discussion:
123 comments Page 11 of 13.
Deepi said:
1 decade ago
Hi Guys,
I have a shortcut method like this kind of problems see this
a:b:c can be calculated easily from a:b and b:c just multiply as shown below
a:b
b:c
-------
a*b:b*b:b*c
So from the problem 2:3 is a:b and 5:8 is b:c
2:3
5:8
-------
2*5:3*5:3*8
answer is 10:15:24
Here given is sum of three number is 98.
that is 10+15+24=49
49=98
15=? => (15*98)/49 = 30.
I have a shortcut method like this kind of problems see this
a:b:c can be calculated easily from a:b and b:c just multiply as shown below
a:b
b:c
-------
a*b:b*b:b*c
So from the problem 2:3 is a:b and 5:8 is b:c
2:3
5:8
-------
2*5:3*5:3*8
answer is 10:15:24
Here given is sum of three number is 98.
that is 10+15+24=49
49=98
15=? => (15*98)/49 = 30.
(1)
RISHIKESH said:
1 decade ago
Thanks alisha.
Murali said:
1 decade ago
If a:b:c=2:3:5 then the ratio of (b+c)/4:(c+a)/4:(a+b)/4 is?
Can any one give answer for this....
Can any one give answer for this....
Ankur saxena said:
1 decade ago
a/b=2/3,b/c=5/8
a+b+c=98
2b/3+b+8b/5=98
b=30
a+b+c=98
2b/3+b+8b/5=98
b=30
Sweet said:
1 decade ago
Let a's amount= z
so b's amount=1210-z
now (4/15)z=(2/5)x(1210-z)
=>
(4/15)z=484-2/5z
=>
(4/15)z+(2/5)z=484
=>
by taking l.c.m (10/15)z=484
=> 10z=7260
=>
z=726
So a's amount=z=726
and b's amount=1210-726=484 ans.
so b's amount=1210-z
now (4/15)z=(2/5)x(1210-z)
=>
(4/15)z=484-2/5z
=>
(4/15)z+(2/5)z=484
=>
by taking l.c.m (10/15)z=484
=> 10z=7260
=>
z=726
So a's amount=z=726
and b's amount=1210-726=484 ans.
Amit said:
1 decade ago
Hey thanks kalpa, its very easy to understand.
Vicky singh said:
1 decade ago
Thanks kalpa for solve such easy method to this question.
Avijeet said:
1 decade ago
Thanks alisha.
You used awesome shortcut:).
You used awesome shortcut:).
Emani Karthik Reddy said:
1 decade ago
Sum of numbers Ax+Bx+Cx=98->1
Ratio of first to second 2:3
second to third 5:8
the ratio A:B::C:D=2:3::5:8
find the ratio A:B:C
i.e A:B:C=2:3::(5*(3/5)):(8*(3/5)).
new ratio is 2:3::3:24/5
A:B:C=2:3:24/5
A:B:c=10:15:24
from 1 we get
10x+15x+24x=98
x=2
second number =15*2=30.
Ratio of first to second 2:3
second to third 5:8
the ratio A:B::C:D=2:3::5:8
find the ratio A:B:C
i.e A:B:C=2:3::(5*(3/5)):(8*(3/5)).
new ratio is 2:3::3:24/5
A:B:C=2:3:24/5
A:B:c=10:15:24
from 1 we get
10x+15x+24x=98
x=2
second number =15*2=30.
Alisha said:
1 decade ago
a+b+c=98
a/b=2/3 and b/c=5/8 and hence
a=2b/3 and c=8b/5
so,
2b/3+8b/5+b=98
34b+15b=98*15
49b=98*15
and finally, b=(98*15)/49=30
a/b=2/3 and b/c=5/8 and hence
a=2b/3 and c=8b/5
so,
2b/3+8b/5+b=98
34b+15b=98*15
49b=98*15
and finally, b=(98*15)/49=30
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